Code operated device



Dec. 12, 1961 v. E. CARBONARA ET AL 3,013,248

CODE OPERATED DEVICE Filed Jan. 22', 1959 4 Sheets-Sheet l 4 m mw m 2v2. 4 N. 5 1 x 7A WM m v. E. CARBONARA ETAL 3,013,248

Dec. 12, 1961 CODE OPERATED DEVICE 4 SheetS- -Sheet 2 Filed Jan. 22,1959 T f w 7 V V 0/ Mw M Dec. 12, 1961 v. E. CARBONARA ET AL 3,013,248

CODE OPERATED DEVICE 4 Sheets-Sheet 3 Filed Jan. 22, 1959 12, 1961 E.CARBONARA ET AL 3,013,248

CODE OPERATED DEVICE Filed Jan. 22, 1959 4 Sheets-Sheet 4 INVENTORE'warm? 5- mead W Arraex/m\ United States Patent 3,013,248 CODE OPERATEDDEVICE Victor E. Carbonara, Manhasset, N.Y., and William G.

Dclp, Pasadena, Calif., assignors to Kollsman Instrument Corporation,Eimhurst, N.Y., a corporation of New York Filed Jan. 22, 1959, Ser. No.788,454 5 Claims. (Cl. 340-164) Our invention relates to code operateddevices and more particularly to an electric lock in the form of a codeoperated device adapted to operate on a succession of accurately timedpulses. On the occurrence of any pulse in the wrong time sequence, theoperation of the lock will be defeated and the lock operating elementswill be restored to the original condition existing before the firstcode pulse. A full properly timed code sequence is, therefore, necessaryto operate the lock and any step by step attempt to defeat the lock willbe frustrated.

In the operation of remote control devices, such as for instance garagedoor openers, it is desirable to permit the user to send a coded signalwhich will initiate operation while at the same time it is necessary toprevent unathorized operation. A garage door opener consists of: a motorfor operating the door, preferably through a reduction gear sufficientlylarge in ratio to be self-locking against any force which could lift thedoor when the motor has stopped; a switch for actuating the motor; meansfor receiving a motor actuating signal; and means (the lock) fortranslating the motor actuating signal into an operation of the motorswitch.

Thus, the car will have some means for generating a series of timedpulses over a short space of time. This may well be a hand-woundclock-work mechanism in the car which, on a quarter turn of a handle,will unwind to create the timed sequence of pulses; any, even crude,clock-work will be accurate over the fifteen seconds or so required togenerate the timed set of code pulses. These pulses may be used tooperate the car headlights in cooperation with a photocell receiver atthe door or may be used in connection with a transmitter on the car anda receiver at the door to generate a succession of timed pulses usableat the lock. Our improved lock is then arranged to operate in responseto such pulses to close the door opening circuit provided the correctnumber of pulses is received in the correct time sequence.

Essentially our invention contemplates a rotatable lock disk and acooperating follower arm biased against a main surface of the disk. Thefollower is secured to the armature of a relay whose energization anddeenergization is controlled by the coded pulses transmitted from thecar.

A track in the shape of an open ring is formed on the main surface ofthe disk projects in an axial direction therefrom and is arrangedconcentrically with respect to the axis of rotation of the disk. Thetrack is further positioned sothat the follower normally rides on thetrack when the relay is both energized and deenergized.

Extending upwardly from the raised track are a plurality of deflectorsarranged in a predetermined relationship. The deflectors are sopositioned that if the relay is energized and deenergized in'the propersequence the follower will remain on the raised track from its entranceend to its exit end. If an incorrect code is utilized to control relayoperation the follower will be engaged by a deflector and be swept offof the projecting track "ice to the main surface until the diskcompletes a revolution.

If the follower remains on the projecting track until the exit endthereof it will engage an actuator formation at the exit end which willdeflect the follower causing it to close a set of normally open actuatorcontacts connected in a circuit controlling a garage door motor so thatthe garage door may be operated. Thus, the follower must be on theprojecting track at the exit end in order for the coded signals toeffect operation of the garage door.

Our invention is distinguished from prior art devices of this type inthat the costly stepping relay of prior art devices has been eliminatedwithout a sacrifice in any desirable operating features. Further, all ofthe elements of our device are stationary until such time as the devicereceives a coded signal combination which may readily open the lock bymanipulating the headlight controls assisted by the flashing bulb, eventhough he might have a poor sense of timing. However, an unauthorizedperson, i.e., one not knowing the combination, who succeeds in startingthe drive motor and flashing the assist indicator, will receive no aidin attempting to open the lock. Thus, the need has been eliminated forproviding a separate means for generating a series of timed code pulses.

The lock disk is normally stationary and is rotated through a completecycle each time coded signals are received by the lock whether or notthe signals comprise the correct code. Since it is preferable totransmit the coded signals from the car to the lock by means of the carheadlights, means are provided whereby the light transmitted by passingcars will not initiate a cycle of the lock disk. This means comprises adelay device which must be continuously actuated by the headlights for ashort interval of time before the motor which drives the lock disk maybe energized. The interval is chosen so as to exceed the continuous timeduration during which the headlights of passing cars could reasonably beexpected to impinge upon the photoelectric device associated with thelock.

Our novel electric lock may also be used to control the closing as wellas the opening of the garage door. This is accomplished by means ofcircuitry which includes the aforesaid actuator contacts. In thecircuitry hereinafter described closing of the door must be preceded bya complete opening thereof.

Accordingly, a primary object of our invention is the provision of anovel electric lock which will operate only on an accurately timedseries of code pulses to close a circuit and which will be defeated onthe occurrence of any incorrectly spaced or timed pulse.

Another object is to provide a novel electric lock including means forassisting the manual control of code pulses required for opening.

Still another object of our invention is to provide a novel electriclock which does not require the stepping relay characteristic of locksof this type but which never theless cannot be opened by one who doesnot know the the proper opening sequence.

A further object of our invention is to provide a novel electric lockincluding provisions for automatic closing as well as opening of agarage controlled thereby.

A still further object is to provide a novel electric lock including arotatable lockdisk including a raised track having deflectors positionedin predetermined relationship thereon, whereby a relay operatedfollower, normally on the raised track, will be deflected from theraised track unless the proper pulse sequence is utilized to energizethe relay. The exit end of the raised track includes a cam formationwhich will deflect the follower into engagement with an actuator if thefollower remains on the raised track for its entire length.

The foregoing and many other objects of our invention will becomeapparent in the following description and drawings in which:

FIGURE 1 is a front elevation of our novel code operated device with theelements in their at rest positions at the end of a complete cycle.

FIGURE 1a is a side elevation of the device of FIG- URE l with theelements in the same position as they occupy in FIGURE 1.

FIGURES 2 and 3 are front elevations of the device of FIGURE 1illustrating the locking disk in two different intermediate positions.

FIGURE 4 is another front elevation of the device of FIGURE 1 with theelements shown at the time when the follower has reached the end of thetrack and is deflected by the actuator formation.

FIGURE 4a is a side elevation illustrating the elements of the device intheir positions illustrated in FIGURE 4.

FIGURE 5 is a fragmentary exploded View of the code operated device ofFIGURE 1.

FIGURE 6 is a schematic wiring diagram of the code operated device ofFIGURE 1.

FIGURE 7 is a side elevation of a signal pickup means which may beutilized as part of my novel device.

FIGURE 8 is a wiring diagram illustrating the manner in which the codematching device may be utilized to control a motor for garage dooroperation.

Now referring to the figures, a local source of energy (notshown) iscontrolled from a remote point to provide a plurality of appropriatelyspaced and timed signals. This source for the unlocking signals isconnected to coil of operating relay 21 which is supported by bracket 22on the chassis 2'3. Coil 20 is provided with a suitable core 24 arrangedto attract armature 25 when coil .20 is energized. Armature 25 ishingedly mounted at 27 on member 28 secured to relay bracket 26, witharmature 25Ihaving one end thereof secured to one end of tension spring29 whose other end is secured to lug 30 of member 28. Thus, armature 25is biased away from core 24 of relay 2 1 by spring29.

Whenever'the headlight beams of a car impinge upon photosensitive device31 current from energy source 32 'sufficient to energize relay coil 20,passes therethrough. In order to prevent stray lights from initiatingoperation, a time delay means 33 is provided. Time delay means 33 'maybe of the type manufactured by the Amperite Company, Inc. designated115N051, and comprises a heater 34 associated with normally opencontacts 35. With relay 21 energized'the normally closed contacts 36thereof open. Thus a complete circuit between L and L exists throughheater 34. This circuit, beginning at L compriseslead 38, heater 34,lead 39, closed contacts 37, lead 40 to contact 41 "of switch 42,contact arm 43, and finally through lead 44 to L When heater 34 has beenenergized for a predetermined interval of time, say five seconds,contacts 35 are thereby closed so that upon subsequent deenergization ofcoil 20, synchronous motor 46 is energized through a circuit from Lcomprising lead 47, motor lead 48, contact 36 of relay 21, leads 49 and50, closed contacts 34 and lead 54 to L The output of motor 46 providesthe input for speed reducer 55 whose output shaft 56, passing through anopening in chassis 23, drives holding cam 57 and lock disk 58 in aclockwise direction with respect to FIGURES 1-5 as indicated by arrow A.The initial rotational movement of holding cam 57 causes the tip 5'8 ofarm 43 to move out of cam recess 59 so that contact arm 43 disengagescontact 41 and engages holding contact 45. Thus, motor 46 is energizedregardless of the condition of contacts 35 and 36 until cam 57 completesa full revolution.

In the at rest, or starting, position'of FIGURE 1 the offset tip 61 ofresilient follower 60, which is secured to relay armature 25, rests upontrack 62 which projects outwardly from the main surface 63 of lock disk58. Raised track 62 is of an open ring shape having an inclined entrance64 and an inclined exit 65.

A plurality of deflectors 66-74 project from track 62, and for thepurposes of illustration only, are arranged in three groups which form aslalom which must be successfully negotiated by follower tip 61, in amanner to be hereinafter explained, in order to unlock our novelelectrick lock. The first group comprises deflectors 6669, the secondgroup comprises deflectors 70-72, and the third group comprisesdeflectors 73 and 74. Each of the deflectors 66-74 is comprised of awire like member bent to a general shape with one arm having an outwardbulge.

In order for follower tip 61 to successfully negotiate slalom 66-74relay 21 must be energized and deencrgized for predetermined intervalswhich are as follows. After time delay means 33 has been actuated toclose contacts 35 relay coil 20 must be deenergized for a first intervalor the time required for the first group of deflectors 66-69 to passopposite follower tip 61. Then relay coil 2% must be energized for asecond interval or the time required for the second group of deflectors70-72 to pass opposite follower tip 61 and finally relay coil 20 must bedeenergized for a third interval or the time required for the thirdgroup of deflectors 73 and 74 to pass opposite follower tip 61.

That is, if relay coil 20 is energized while any of the deflectors ofthe first group 66-69 or the third group 73, 74 are opposite followertip 61, the tip 61 will be swept over the inside edge 75 of track 62.Resilient follower 6% is self biased toward disk surface 63 so that whentip 61 passes over edge 75 tip 61 will be forced against disk surface 63and will remain against this surface even though coil 20 is deenergizeduntil exit passes tip 61 and continued rotation of disk 58 causes tip 61to ride up on inclined entrance 64.

The preceding operation is illustrated in FIGURE 2 wherein follower 60occupies the solid line position when relay 21 is deenergized and thephantom position when relay 21 is energized. Thus, energization of relay21 when disk 58 is in the position of FIGURE 2 moves follower tip 61against the lower side of deflector 67. With continued rotation of disk58 the upper side of the next deflector 68 will engage tip 61 and guidefollower 60 toward the center of disk 58 so that tip 61 passes over theinside edge 75 of track 62.

As seen in FIGURE 3, a similar operation takes place when the deflectorsof the second group -72 are opposite follower tip 61. In FIGURE 3follower 60 is in the solid line position when relay 21 is energized andin the phantom position when relay 21 is deenergized. Thus,deenergization relay 21 when disk 58 is in the position of FIGURE 3moves follower tip 61 against the lower side of deflector 71. Withcontinued rotation of disk 58 the upper side of the next deflector 72will engage tip 61 and guide follower 60 away from the center of disk 58so that tip 61 passes over the outside edge 76 of track 62. Once tip 61passes over outside edge 76 tip 61 cannot return to track 62 exceptthrough entrance 64.

It is to be noted that tip 61 is of a greater length than the combinedheights of track 62 and any one of the deflectors 66-74 so that when tip61 rides on disk surface 63 all of the deflectors 6644 Will pass freelybeneath follower 69.

Thus, in order for follower tip 61 to successfully negotiate the slalomformed by deflectors 66-74 the followmust take place without deviationonce lock disk 58 commences to rotate.

(1) Relay 21 must remain deenergized while deflectors 66-63 are oppositefollower tip 61 and until the leading end 7 of deflector 69 passes tip61 then track 62 is provided with an actuator formation 82 whichprojects away from disk surface 63. When tip 61 rides up on formation 82(FIGURES 4 and 4a) follower 60 will be deflected so that a deformedportion 83 thereof engages switch arm 84 to close normally open actuatorcontacts 85 which remain closed only for the short interval of time thattip 61 is on formation 82 which is a sufficient time interval to operatethe garage door motor 86 (FIGURE 8) as will be hereinafter explained.

The peripheral edge of lock disk 58 is provided with a series of equallyspaced notches as well as a single time delay interlock lobe 90.Follower switch arm 52 is self biased toward the edge of lock disk 58.Thus when bend 91 of arm 52 is disposed in a peripheral notch arm 52engages contact 53 and when bend 91 engages lobe 90 am 52 engagescontact 51. It is to be noted that arm 52 engages contact 51 whenholding cam 57 permits arm 43 to engage contact 41 (FIGURE 6).

Code assist light bulb 92 is normally off. When the contacts 35 of timedelay device 33 are closed light bulb 92 is energized by source 32through a circuit beginning at L and comprising lead 93, bulb 92, lead94, switch arm 52, contact 51, lead 95, lead 50, contacts 35, and lead54 to L Thus, when bulb 92 first lights this indicates thatdeenergization of coil 20, by turning off of the headlights, willenergize motor 46 as hereinbefore explained.

Once motor 46 begins to operate, lock disk 58 rotates so that lobe 90disengagcs bend 91 and arm 52 disengages contact 51. During the rotationof disk 58 arm 52 alternately engages and disengages contact 53 withoutengaging contact 51. When arm 52 engages contact 53 light bulb 92 isenergized through lead 96 connected between L and contact 53. It is tobe noted that the peripheral notches of lock disk 58 are equally spacedso that code assist light 92 flashes in an orderly fashion to indicateto the driver when his headlights are to be turned on .and off.

FIGURE 7 illustrates a signal pickup device 101 which may be utilized toreceive light pulses from the car headlights. Device'101 is comprised ofan L-shaped housing 102 having a vertical elongated arm with aphoto-electric cell 31 disposed therein at the top free end thereof.Window-104 is located'at the free end of the horizontal leg.

.Mirror 105 is positioned at the juncture between the arm and leg ofhousing 102 and is inclined to reflect light rays passing through window104 substantially parallel to the vertical leg upward to cell 31. Window104 is oppositely inclined with respect to mirror 105 for purposes ofdrainage as well as to admit more light coming from below than fromabove. A water tight covering 106 is placed at the free end of thevertical leg with cable 107 projecting through covering 106 andextending to the other circuitry of FIGURE 6.

tor contacts 85 are momentarily closed with the circuit elements in theposition of FIGURE 8 a circuit is completed between L and L Thiscircuit, beginning at L comprises manual stop switch 120, closedactuator contacts 85, ganged upper limit switches 121, 122 and relaycoil 123 to L Thus, relay coil 123 is energized thereby operating switcharm 125, which is pivoted at '126, toward coil 123.

This brings switch arm 125 in contact with motor contact 129 therebyplacing winding 131 in parallel with the series combination of winding132 and motor capacitor 133 with the parallel combination beingconnected across L and L When motor 86 is connected and energized inthis manner it will rotate in a forward direction or the directionrequired to open the garage door. At the same time switch arm 125engages holding contact 127 thereby completing a circuit through coil123 which by-passes actuator contacts so that upon opening thereof motor86 will continue to operate. When the door reaches the top of itstravel, dogs (not shown) carried by the door operate upper limitswitches 121, 122 to interrupt the circuit to coil 123 thereby releasingcontact arm which moves to a central position being urged to thisposition by centering springs 134, 135 interrupting the power to motor86.

A subsequent closing of actuator contacts 85 completes a circuit betweenL and L which includes relay coil 124. This circuit, beginning at Lcomprises manual stop switch 120, actuator contacts 85, back contacts136 of upper limit switch 121, bottom limit switch 137, and relay coil124 to L Thus, relay coil 124 is energized thereby operating switch arm125 toward coil 124.

This brings switch arm 125 in contact with motor contact 130 therebyplacing winding 132 in parallel with the series combination of winding131 and capacitor 133 with the parallel combination being connectedacross L and L When motor 86 is connected and energized in this mannerit will rotate in reverse direction or the direction required to closethe garage door. At the same time switch arm 125 engages holding contact128 thereby completing a circuit through coil 124 which by-passesactuator contacts 85 so that upon opening thereof motor 86 will continueto operate. When the door reaches the bottom of its travel, another door(not shown) carried by the door operates lower limit switch 137 tointerrupt the circuit to coil 124 thereby releasing contact arm 125which then moves to its central position interrupting power to motor 86.

Relay coils 123 and 124 are so proportioned that when one is energized,the subsequent energization of the other before deenergization of thefirst coil will not cause the switch arm 125 to be attracted toward theother coil.

It is readily seen that the opening of manual stop switch 120 will causethe motor to stop regardless of the position of the other circuitelements. Switch is utilized for manual control. That is, when switcharm 151 engages contact 152 relay coil 123 is energized if upper limitswitch 122 is closed and when switch arm 15 engages contact 153 relaycoil 124 is energized if lower limit switch 137 is closed.

While this invention has been illustrated with deflectors 66-74 arrangedin a particular manner, it is obvious many diiferent deflectorarrangements may be utilized. By merely varying the positions of thedeflectors by merely placing the ends thereof in different holes 9 oftrack 62, the combination of the code operated device may be changed.

Although we have here described preferred embodiment of our novelinvention, many variations and modifications will now be apparent tothose skilled in the art, and we therefore prefer to be limited, not bythe specific disclosure herein, but only by the appending claims.

We claim:

1. A code operated electric lock device, openable in response to acombination 'of correctly coded pulses, in-

7 cluding a first means normally stationary in a start position andbeing movable through a cycle back to said start position; said firstmeans including a track having an entrance and an exit; a second meansincluding a follower operatively positioned to ride on said track; areceiver operatively connected to said second means whereby said pulsesare translated into motion of said follower; said first means includinga formation constructed to guide said follower through said entrance onto said track and being further constructed to prevent said followerfrom entering said track except at said entrance; a slalom comprised ofa plurality of deflectors operatively positioned to engage and therebydeflect said follower off of said track before said exit when anincorrectly coded pulse is picked up by said receiver; said followerleaving said track at said exit only when correctly coded pulses arepicked up by said receiver; said first means comprising a body rotatableabout an axis; said track comprising a ring formation extendingoutwardly from a first surface of said body and arranged concentricallyabout said axis.

2. A code operated electric lock device, openable in response to acombination of correctly coded pulses, including a first means normallystationary in a start position and being movable through a cycle back tosaid start position; said first means including a track having anentrance and an exit; a second means including a follower operativelypositioned to ride on said track; a receiver operatively connected tosaid second means whereby said pulses are translated into motion of saidfollower; said first means including a formation constructed to guidesaid follower through said entrance on to said track and being furtherconstructed to prevent said follower from entering said track except atsaid entrance; a slalom com prised of a plurality of deflectorsoperatively positioned to engage and thereby deflect said follower offof said track before said exit when an incorrectly coded pulse is pickedup by said receiver; said follower leaving said track at said exit onlywhen correctly coded pulses are picked up by said receiver; said firstmeans comprising a body rotatable about an axis; said track comprising aring formation extending outwardly from a first surface of said body andarranged concentrically about said axis; means biasing said follower ina direction parallel to said axis toward said first surface; some ofsaid plurality of deflectors being arranged to deflect said followerover a first side of said track and others of said plurality ofdeflectors being arranged to deflect said follower over a second side ofsaid track; said formation being said second side.

3. A code operated electric lock device, openable in response to acombination of correctly coded pulses, including a first means normallystationary in a start position and being movable through a cycle back tosaid start position; said first means including a track having anentrance and an exit; a second means including a follower operativelypositioned to ride on said track; a received operatively connected tosaid second means whereby said pulses are translated into motion of saidfollower; said first means including a formation constructed to guidesaid follower through said entrance on to said track and being furtherconstructed to prevent said follower from entering said track except atsaid entrance; a slalom comprised of a plurality of deflectorsoperatively positioned to engage and thereby deflect said follower offof said track before said exit when an incorrectly coded pulse is pickedup by said receiver; said follower leaving said track at said exit onlywhen correctly coded pulses are picked up by said receiver; said firstmeans comprising a body rotatable about an axis; said track comprising aring formation extending outwardly from a first surface of saidv bodyand arranged concentrically about said axis; means biasing said followerin a direction parallel to said axis toward said first surface; some ofsaid plurality of deflectors being arranged to deflect said followerover a first side of said track and others of said plurality ofdeflectors being arranged to deflect said follower over a second side ofsaid track; said formation being said second side; means including arelay having an armature movable between a first and a second position;said followe-r being secured to said armature and being movable thereby;said follower being movable by said armature to successfully negotiatesaid slalom when correctly coded pulses are picked up by said receiver.

4. A code operated electric lock device, openable in response to acombination of correctly coded pulses, including a first means normallystationary in a start position and being movable through a cycle back tosaid start position; said first means including a track having anentrance and an exit; a second means including a follower operativelypositioned to ride on said track; a receiver operatively connected tosaid second means whereby said pulses are translated into motion of saidfollower; said first means including a formation constructed to guidesaid follower through said entrance on to said track and being furtherconstructed to prevent said follower from entering said track except atsaid entrance; a slalom comprised of a plurality of deflectorsoperatively positioned to engage and thereby deflect said follower offof said track before said exit when an incorrectly coded pulse is pickedup by said receiver; said follower leaving said track at said exit onlywhen correctly coded pulses are picked up by said receiver; said firstmeans comprising a body rotatable about an axis; said track comprising aring formation extending outwardly from a first surface of said body andarranged concentrically about said axis; means biasing said follower ina direction parallel to said axis toward said first surface; some ofsaid plurality of deflectors being arranged to deflect said followerover a first side of said track and others of said plurality ofdeflectors being arranged to deflect said follower over a second side ofsaid track; said formation being said second side; means including arelay having an armature movable between a first and a second position;said follower being secured to said armature and being movable thereby;said follower being movable by said armature to succesfully negotiatesaid slalom when correctly coded pulses are picked up by said receiver;code assist means operated by said first means while said first means ismoving through said cycle; said rotatable body including depressionsalong the periphery thereof; a switch means including a follower inengagement with said periphery; said code assist means being alternatelyenergized and de-energized by said switch means.

5. A code operated electric lock device, openable in response to acombination of correctly coded pulses, including a first means normallystationary in a start position and being movable through a cycle back tosaid start position; said first means including a track having anentrance and an exit; a second means including a follower operativelypositioned to ride on said track; a receiver operatively connected tosaid second means whereby said pulses are translated into motion of saidfollower; said first means including a formation constructed to guidesaid follower through said entrance on to said track and being furtherconstructed to prevent said follower from entering said track except atsaid entrance; a slalom comprised of a plurality of deflectorsoperatively positioned to engage and thereby deflect said follower offof said track before said exit when an incorrectly coded pulse is pickedup by said receiver; said follower leaving said track at said exit onlywhen correctly coded pulses are picked up by said receiver; said firstmeans comprising a body rotatable about an axis; said track comprising aring formation extending outwardly from a first surface of said body andarranged concentrically about said axis; means biasing said follower ina direction parallel to said axis toward said first surface; some ofsaid plurality of deflectors being arranged to deflect said followerover a first side of 9 said track and others of said plurality ofdeflectors being arranged to deflect said follower over a second side ofsaid track; said formation being said second side; means including arelay having an armature movable between a first and a second position;said follower being secured to said armature and being movable thereby;said follower being movable by said armature to successfully negotiatesaid slalom when correctly coded pulses are picked up by said receiver;code assist means operated by said first means while said first means ismoving through said cycle; delay means normally in a first positionoperable to a second position by a coded signal whose duration exceeds apredetermined minimum time interval; driving means operatively connectedto said first means for movement thereof through said 15 10 cycle; saiddelay means being operatively connected to said driving means wherebyoperation of said delay means to its said second position is eflectiveto condition said driving means to initiate said cycle.

References Cited in the file of this patent UNITED STATES PATENTS1,205,460 Lyons Nov. 21, 1916 10 21,544,330 Koenig Mar. 6, 1951 FOREIGNPATENTS 824,957 France Feb. 21, 1938

